In the packaging of integrated circuits, a plurality of package components may be bundled in the same package. The package components may include device dies, interposers, package substrates, printed circuit boards (PCB), and the like.
Typically, before the packaging, the device wafers are tested (probed), so that known-good-dies can be selected and packaged, while failed dies are not packaged. After the packaging is finished, the resulting packages are also probed, so that failed packages may be identified. The failed packages may be caused by defective joints, the damages occurring in the packaging processes, and the problems introduced by interposers, package substrates, and PCBs. However, after the packaging is finished, even if defective packages may be identified in the test, it is difficult to isolate the exact locations of the problems, and hence it is difficult to use the probing results to guide the future manufacturing process.